1. Field of the Invention
The present invention relates to a method of manufacturing an active material and a method of manufacturing a lithium-ion secondary battery.
2. Related Background Art
LiCoO2 has widely been in use as a positive electrode active material for lithium-ion secondary batteries. However, it has been pointed out that LiCoO2 incurs high material cost and low thermal stability which is problematic in terms of safety. As positive electrode active materials which overcome these problems, phosphate-based positive electrode active materials such as LiFePO4 and LiVOPO4 have been attracting attention. Among the phosphate-based positive electrode active materials, LiVOPO4 has been known as a compound which can achieve a 4-V class charge/discharge voltage (see Japanese Translated International Patent Application Laid-Open NO. 2003-520405, Journal of The Electrochemical Society, 151(6) A794-A800 (2004), and Electrochemistry, 71 No. 12 (2003), 1108-1110).